The Target Group Index has been one of the most successful research innovations over the period covered by this book. Despite initial worries by the industry about overloading respondents, it collects data about a wide range of product behaviour, media, demographic and other data from each respondent. The main applications are to media planning since it allows the most natural target definitions of all: classifications by product usage or purchase. At the same time, other interlaced analyses are possible.
The TGI was launched in Britain five years ago. This paper does not set out to describe how the service operates or how, in general, it is used to judge the relative selectivity in reaching target markets of individual publications, on the one hand, or of individual television areas on the other. The Target Group Index was established by BMRB in 1968-69 as a syndicated research service available to advertisers, agencies and media owners. Fieldwork is continuous and involves 25,000 interviews over a 12 month period with adults aged 15 or over in Great Britain. While most of the demographic classifications are recorded at a personal interview the answers to the product and media questions are collected by self-completion.